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Stock-Based Compensation - Effect of Recording Stock-Based Compensation (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 49,194	$ 27,262	$ 24,378
Windfall tax effect on stock-based compensation	(2,244)	(8,277)	(11,071)
Net effect on net income	$ 46,950	$ 18,985	$ 13,307
Basic	$ 0.86	$ 0.35	$ 0.25
Diluted	$ 0.85	$ 0.35	$ 0.24
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 47,005	$ 24,883	$ 22,428
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	73	98	529
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 2,116	$ 2,281	$ 1,421

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